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A theory is either true or false. Galileo s observations of [#permalink]

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20 Dec 2007, 17:53

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A theory is either true or false. Galileo’s observations of Jupiter’s satellites showed that the Ptolemaic theory of the motion of celestial bodies is false. Therefore, since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account,Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory.The argument above is open to the objection that it makes the questionable assumption thatA. whoever first observed something inconsistent with the truth of the Ptolemaic theory should be credited with having proved that theory falseB. there are some possible observations that would be inconsistent with the account given by the Copernican theory but consistent with the account given by the Ptolemaic theoryC. the Ptolemaic and Copernican theories, being inconsistent, cannot both be based on exactly the same evidenceD. numerous counterexamples were necessary in order to show the Ptolemaic theory to be falseE. the Ptolemaic and Copernican theories, being inconsistent, cannot both be false

Re: A theory is either true or false. Galileo s observations of [#permalink]

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20 Dec 2007, 18:43

gregspirited wrote:

A theory is either true or false. Galileo’s observations of Jupiter’s satellites showed that the Ptolemaic theory of the motion of celestial bodies is false. Therefore, since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account,Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory.The argument above is open to the objection that it makes the questionable assumption thatA. whoever first observed something inconsistent with the truth of the Ptolemaic theory should be credited with having proved that theory falseB. there are some possible observations that would be inconsistent with the account given by the Copernican theory but consistent with the account given by the Ptolemaic theoryC. the Ptolemaic and Copernican theories, being inconsistent, cannot both be based on exactly the same evidenceD. numerous counterexamples were necessary in order to show the Ptolemaic theory to be falseE. the Ptolemaic and Copernican theories, being inconsistent, cannot both be false

Re: A theory is either true or false. Galileo s observations of [#permalink]

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20 Dec 2007, 21:52

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gregspirited wrote:

A theory is either true or false. Galileo’s observations of Jupiter’s satellites showed that the Ptolemaic theory of the motion of celestial bodies is false. Therefore, since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account,Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory.The argument above is open to the objection that it makes the questionable assumption thatA. whoever first observed something inconsistent with the truth of the Ptolemaic theory should be credited with having proved that theory falseB. there are some possible observations that would be inconsistent with the account given by the Copernican theory but consistent with the account given by the Ptolemaic theoryC. the Ptolemaic and Copernican theories, being inconsistent, cannot both be based on exactly the same evidenceD. numerous counterexamples were necessary in order to show the Ptolemaic theory to be falseE. the Ptolemaic and Copernican theories, being inconsistent, cannot both be false

E. lets say the theories can both be false, then the argument falls apart.

Re: A theory is either true or false. Galileo s observations of [#permalink]

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20 Dec 2007, 22:49

GMATBLACKBELT wrote:

gregspirited wrote:

A theory is either true or false. Galileo’s observations of Jupiter’s satellites showed that the Ptolemaic theory of the motion of celestial bodies is false. Therefore, since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account,Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory.The argument above is open to the objection that it makes the questionable assumption thatA. whoever first observed something inconsistent with the truth of the Ptolemaic theory should be credited with having proved that theory falseB. there are some possible observations that would be inconsistent with the account given by the Copernican theory but consistent with the account given by the Ptolemaic theoryC. the Ptolemaic and Copernican theories, being inconsistent, cannot both be based on exactly the same evidenceD. numerous counterexamples were necessary in order to show the Ptolemaic theory to be falseE. the Ptolemaic and Copernican theories, being inconsistent, cannot both be false

E. lets say the theories can both be false, then the argument falls apart.

Re: A theory is either true or false. Galileo s observations of [#permalink]

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21 Dec 2007, 00:11

[quote="gregspirited"]A theory is either true or false. Galileo’s observations of Jupiter’s satellites showed that the Ptolemaic theory of the motion of celestial bodies is false. Therefore, since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account,Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory.The argument above is open to the objection that it makes the questionable assumption
that
A. whoever first observed something inconsistent with the truth of the Ptolemaic theory should be credited with having proved that theory false
B. there are some possible observations that would be inconsistent with the account given by the Copernican theory but consistent with the account given by the Ptolemaic theory
C. the Ptolemaic and Copernican theories, being inconsistent, cannot both be based on exactly the same evidence
D. numerous counterexamples were necessary in order to show the Ptolemaic theory to be false
E. the Ptolemaic and Copernican theories, being inconsistent, cannot both be false

Because Galileo's theory and Copernican theory prove that the Ptolemaic one is false, they are true. So, if the Ptolemaic theory is false, the Copernican one cannot be false as well. E is correct

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Re: A theory is either true or false. Galileo s observations of [#permalink]

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25 Feb 2013, 03:09

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I want to know the meaning of this statement...."The argument above is open to the objection that it makes the questionable assumption that "Should we look up for a false assumption? How could we do that?
_________________

Re: A theory is either true or false. Galileo s observations of [#permalink]

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25 Feb 2013, 08:50

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when they say that argument is wrong because of questionable assumption then we have to make that faulty link exposed .and thats exactly what E is doing .in simple terms what is argument saying ? lets say argument makes a claim that X is wrong then it says Y is inconsistent with X then it concludes that Y is right .what is wrong in this argument .that fact that it assumes that two inconsistent things cannot be wrong at the same time .this is what E talks

Re: A theory is either true or false. Galileo s observations of [#permalink]

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21 Mar 2013, 00:39

gregspirited wrote:

A theory is either true or false. Galileo’s observations of Jupiter’s satellites showed that the Ptolemaic theory of the motion of celestial bodies is false. Therefore, since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account,Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory.The argument above is open to the objection that it makes the questionable assumption thatA. whoever first observed something inconsistent with the truth of the Ptolemaic theory should be credited with having proved that theory falseB. there are some possible observations that would be inconsistent with the account given by the Copernican theory but consistent with the account given by the Ptolemaic theoryC. the Ptolemaic and Copernican theories, being inconsistent, cannot both be based on exactly the same evidenceD. numerous counterexamples were necessary in order to show the Ptolemaic theory to be falseE. the Ptolemaic and Copernican theories, being inconsistent, cannot both be false

Re: A theory is either true or false. Galileo s observations of [#permalink]

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08 Aug 2013, 12:34

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gregspirited wrote:

A theory is either true or false. Galileo’s observations of Jupiter’s satellites showed that the Ptolemaic theory of the motion of celestial bodies is false. Therefore, since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account,Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory.The argument above is open to the objection that it makes the questionable assumption thatA. whoever first observed something inconsistent with the truth of the Ptolemaic theory should be credited with having proved that theory falseB. there are some possible observations that would be inconsistent with the account given by the Copernican theory but consistent with the account given by the Ptolemaic theoryC. the Ptolemaic and Copernican theories, being inconsistent, cannot both be based on exactly the same evidenceD. numerous counterexamples were necessary in order to show the Ptolemaic theory to be falseE. the Ptolemaic and Copernican theories, being inconsistent, cannot both be false

When Galileo's observation proved Ptolemic theory is false, why was the copernican theory automatically accepted? The passage is assuming that both theories cannot be false.

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A theory is either true or false. Galileo’s observations of Jupiter’s satellites showed that the Ptolemaic theory of the motion of celestial bodies is false. Therefore, since the Copernican theory of planetary motion is inconsistent with the Ptolemaic account,Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory.The argument above is open to the objection that it makes the questionable assumption thatA. whoever first observed something inconsistent with the truth of the Ptolemaic theory should be credited with having proved that theory falseB. there are some possible observations that would be inconsistent with the account given by the Copernican theory but consistent with the account given by the Ptolemaic theoryC. the Ptolemaic and Copernican theories, being inconsistent, cannot both be based on exactly the same evidenceD. numerous counterexamples were necessary in order to show the Ptolemaic theory to be falseE. the Ptolemaic and Copernican theories, being inconsistent, cannot both be false

Hi,

Let me share my two cents here.

The question stem requires us to look for the questionable assumption made by the argument.

Let’s first try to deconstruct the argument:

What is the conclusion here?

Galileo’s observations of Jupiter’s satellites proved the truth of the Copernican theory.

What is the basis of this conclusion?

1) A theory is either true or false. Ptolemaic theory is shown to be false.

2) Copernican theory of planetary motion is inconsistent with the Ptolemaic account,

Thus, the argument concludes that Copernican theory is true because it is inconsistent with Ptolemaic theory which is false. Let’s take an example:

If I say that XYZ flower is red and you say that XYZ flower is blue.

Now, we are inconsistent. Right? But if I am proven wrong i.e. the flower is not red, does that mean that you are correct i.e. the flower is blue? No. The flower could be pink or purple or any other color.

Thus, it is possible that though your answer is inconsistent with mine, it is also wrong.

Similarly, it’s possible that though Copernican theory is inconsistent with Ptolemaic theory, it is also false. However, the conclusion states that Copernican theory is true and thus the in-built assumption of the argument is that if two theories are inconsistent with each other, both of them cannot be false.

With this understanding, let’s look at the option statements:

A. whoever first observed something inconsistent with the truth of the Ptolemaic theory should be credited with having proved that theory is false

This statement discusses who should be given the credit to prove that Ptolemaic theory is false. We are given Ptolemaic is false. Who should be given credit is not the focus of the argument. Thus, this choice is incorrect.

B. there are some possible observations that would be inconsistent with the account given by the Copernican theory but consistent with the account given by the Ptolemaic theory

This statements talks about the observations that would be inconsistent with Copernican theory but consistent with Ptolemaic theory. However, we are only concerned with Galileo’s observations in this argument, not other observations. Thus, this choice is an irrelevant and incorrect choice.

C. the Ptolemaic and Copernican theories, being inconsistent, cannot both be based on exactly the same evidence

This statement is about the basis of both the theories; however, whether or not these theories are based on the same evidence, the conclusion of the argument is unaffected. In the argument, we are concerned about the impact of one set of observations on the truth of these theories; we don’t know the original basis of any of these theories. Therefore, basis of the theories is not relevant to the argument. Thus, this is an incorrect choice.

D. numerous counterexamples were necessary in order to show the Ptolemaic theory to be false

We know from the passage that Galileo’s observations showed that the Ptolemaic theory is false This option tells us that it required numerous counter examples to show this result; however, our task is to look for the assumption that the argument makes while drawing the conclusion about the truthness of Copernican theory. Thus, this choice is incorrect.

E. the Ptolemaic and Copernican theories, being inconsistent, cannot both be false

This option identifies with our pre-thinking. The argument fails to consider that despite being inconsistent, both the theories can be false. This choice states the built-in assumption of the argument.

If we negate this option we get,the Ptolemaic and Copernican theories, being inconsistent, can both be false

It shows that Copernican can be false, even if it is inconsistent with Ptolemaic theory. As we can see this breaks down the conclusion, this is the correct choice.

Re: A theory is either true or false. Galileo s observations of [#permalink]

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01 Dec 2015, 12:12

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